General information, not medical advice. In an emergency, call Triple Zero (000). The NSW Poisons Information Centre gives advice on bites, stings and poisons on 13 11 26.
Native or not
Not every rat near bushland is an introduced one. The Australian Museum describes the bush rat as a native rat of forests, woodlands and heath, grey to grey-brown or reddish above, with rounded ears and a relatively short tail. It prefers the dense understorey of the forest, shelters in short burrows under logs or rocks, eats fungi, grasses, fruit, seeds and insects, and is not often found in urban areas.
That matters, because all native mammals are protected in New South Wales by the Biodiversity Conservation Act 2016. If an animal in the garden might be native, it is worth knowing which you have before setting a trap or bait.
What rodents can pass on
NSW Health’s factsheet on rodent-borne infectious diseases was written for a mouse plague, and names four kinds of illness people can catch from mice. Rats appear in it too: the leptospirosis bacteria may be present in mouse and rat urine.
| Disease | How it reaches people | What it can cause |
|---|---|---|
| Leptospirosis | Bacteria in mouse and rat urine enter through cuts or grazes, and occasionally through the lining of the mouth, nose and eyes. | Fever, headache, sore muscles, chills, vomiting, red eyes. Treated with antibiotics. |
| Lymphocytic choriomeningitis virus (LCMV) | Usually from contact with the urine, droppings or saliva of infected rodents. | Mild, or a flu-like illness and sometimes meningitis. |
| Rat bite fever | The bite of an infected animal, or water or food contaminated by rodent urine or droppings. | Fever, muscle pain, rash, joint pain, vomiting, headache. Treated with antibiotics. |
| Gut infections such as salmonellosis, campylobacteriosis and cryptosporidiosis | Direct contact with rodents, or contaminated food preparation surfaces. | Diarrhoea, fever, stomach pain, headache, vomiting, aches, lethargy. |
Leptospirosis can become severe, NSW Health warns, with kidney failure, jaundice, bleeding and breathing complications, and it can sometimes be fatal. Symptoms usually start 5 to 14 days after infection. If you fall ill in the weeks after possible contact with animal urine or a contaminated place, tell your doctor about the exposure. Gardening and bushwalking are among the activities it names as a risk.
Cleaning up after them
Say you open a garden shed on the bush side of the yard and find droppings along a shelf, chewed seed packets and a dead mouse behind the mower. Following NSW Health’s factsheet, step by step:
- Cover any cuts or grazes on your hands and arms with a waterproof dressing.
- Put on gloves and waterproof protective clothing and footwear.
- Pick up the carcass. If someone in the house is pregnant or immunosuppressed, it is better that someone else does this part.
- Clean the shelf and floor with disinfectant or a bleach solution.
- Throw out the chewed packets: NSW Health advises against eating food rodents may have had access to.
- Wash any clothing or bedding that touched urine or droppings in hot water with laundry detergent.
- Wash your hands with soap and dry them, especially before you eat.
- Seal holes and gaps, and move stored food into thick, well-sealed containers.
Inside the house, the same factsheet adds: clean up spills and leftover food promptly, and don’t set mouse traps near where food is prepared.
If a rodent bites
Clean the wound with soap and water straight away. Dry it, apply an antibiotic cream and a clean bandage, and seek medical attention: you may need a tetanus immunisation, and sometimes antibiotics are given to prevent infection. As it heals, see a doctor if the skin turns warm, red or painful.
Snails, slugs and rat lung worm
Gardens near the bush have another rodent link that is easy to miss. Rat lung worm is a parasite that lives mainly in rats; its larvae pass out in their droppings and infect snails and slugs. People can be infected by eating a raw snail or slug, or unwashed lettuce and other raw leafy vegetables carrying their slime. Most people have no symptoms or mild ones; very rarely it infects the brain, and it is occasionally fatal.
- Wash fresh vegetables and lettuce well before eating.
- Supervise infants and young children where they may find snails and slugs.
- Wash your hands once you finish in the garden, or after touching a snail or slug.
- Think about keeping snail and slug numbers down near the vegetable patch, and vermin down around the house.
Baits
Mouse baits must always be used as the label instructs, and baits licensed for agricultural use must never be used in the home. Keep children and pets away from where baits have been laid. NSW Health singles out snail pellets and rodent baits as products where young children must be kept from eating them by accident. If anyone swallows one, the NSW Poisons Information Centre says not to wait for symptoms but to call it on 13 11 26; if they are unconscious or not breathing, call Triple Zero (000) and start CPR.